The present invention relates in general to automotive restraint systems, and more specifically to a system for monitoring seat belt use.
Active restraints, such as seat belts, require each vehicle occupant to manually engage his or her seat belt. The engaged state of seat belts is often electrically monitored, and reminder signals are given when an occupant fails to engage their seat belt.
Since a reminder is useful only when a particular seat belt is disengaged and the respective seat is actually occupied, typical prior art systems use seat occupancy sensors to determine the presence of an occupant in a particular seat. Such sensors typically comprise a load-responsive electrical switch installed within the seat. These prior art systems also require special seat construction and wiring.
In view of the wide acceptance and use of seat belts, especially by drivers, and the practice of many drivers to insure that all passengers are buckled up before driving, it is very useful to know if a seat belt becomes disconnected or disengaged during driving. The driver cannot easily monitor the seat belt use of passengers, especially rear seat passengers, during driving since his/her attention is directed to the act of driving. However, due to reconfigurable seating arrangements, specialized seats, and other seat packaging issues, rear seat occupancy sensors are sometimes not available.